package io.protostuff.mojo;

import java.io.File;
import java.net.MalformedURLException;
import java.net.URL;
import java.util.ArrayList;
import java.util.List;

import org.codehaus.classworlds.ClassRealm;
import org.codehaus.plexus.component.annotations.Component;
import org.codehaus.plexus.component.configurator.AbstractComponentConfigurator;
import org.codehaus.plexus.component.configurator.ComponentConfigurationException;
import org.codehaus.plexus.component.configurator.ComponentConfigurator;
import org.codehaus.plexus.component.configurator.ConfigurationListener;
import org.codehaus.plexus.component.configurator.converters.composite.ObjectWithFieldsConverter;
import org.codehaus.plexus.component.configurator.converters.special.ClassRealmConverter;
import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluationException;
import org.codehaus.plexus.component.configurator.expression.ExpressionEvaluator;
import org.codehaus.plexus.configuration.PlexusConfiguration;

/**
 * A custom ComponentConfigurator which adds the project's runtime classpath elements to the classpath
 *
 * Source: http://mail-archives.apache.org/mod_mbox/maven-users/200808.mbox/%3C18785907.post@talk.nabble.com%3E
 *
 * @author Brian Jackson (original implementation)
 * @author Konstantin Shchepanovskyi (fixed issues with Java 8 javadoc tool)
 */
@Component(role = ComponentConfigurator.class, hint = "include-project-dependencies")
public class IncludeProjectDependenciesComponentConfigurator extends AbstractComponentConfigurator
{

    public void configureComponent(Object component, PlexusConfiguration configuration,
            ExpressionEvaluator expressionEvaluator, ClassRealm containerRealm,
            ConfigurationListener listener)
            throws ComponentConfigurationException
    {

        addProjectDependenciesToClassRealm(expressionEvaluator, containerRealm);
        converterLookup.registerConverter(new ClassRealmConverter(containerRealm));
        ObjectWithFieldsConverter converter = new ObjectWithFieldsConverter();
        converter.processConfiguration(converterLookup, component, containerRealm.getClassLoader(), configuration,
                expressionEvaluator, listener);
    }

    private void addProjectDependenciesToClassRealm(ExpressionEvaluator expressionEvaluator, ClassRealm containerRealm)
            throws ComponentConfigurationException
    {
        List<String> runtimeClasspathElements;
        try
        {
            // noinspection unchecked
            runtimeClasspathElements = (List<String>) expressionEvaluator
                    .evaluate("${project.runtimeClasspathElements}");
        }
        catch (ExpressionEvaluationException e)
        {
            throw new ComponentConfigurationException(
                    "There was a problem evaluating: ${project.runtimeClasspathElements}", e);
        }

        // Add the project dependencies to the ClassRealm
        final URL[] urls = buildURLs(runtimeClasspathElements);
        for (URL url : urls)
        {
            containerRealm.addConstituent(url);
        }
    }

    private URL[] buildURLs(List<String> runtimeClasspathElements) throws ComponentConfigurationException
    {
        // Add the projects classes and dependencies
        List<URL> urls = new ArrayList<URL>(runtimeClasspathElements.size());
        for (String element : runtimeClasspathElements)
        {
            try
            {
                final URL url = new File(element).toURI().toURL();
                urls.add(url);
            }
            catch (MalformedURLException e)
            {
                throw new ComponentConfigurationException("Unable to access project dependency: " + element, e);
            }
        }

        // Add the plugin's dependencies (so Trove stuff works if Trove isn't on
        return urls.toArray(new URL[urls.size()]);
    }

}
